A plugin for reformer to handle the super annoying problem of username validation testing while filling out a form.

The problems:

You want to run a debounced check as a user is typing into the field.

You want to validate that with some server-side check. But, you also have to account for the fact that results may come back out of order. So we only care about results for requests that checked the current data.

You want a hard enforcement check before submitting the form.

You want to support existing data in the form and not check if it's just the same value as when you started.

If it violates simple formatting rules you don't want to do the server-side check at all.

You want to be able to customize a message saying that the username they picked is, or isn't available.

You want to be able to show that container whenever something relevant is happening, but not if there's nothing wrong.

You want to be able to show a spinner or some type of loading graphic when the server checks are happening.